title: Evaluation of hair loss in cats occurring after treatment with a topical flea control product.
abstract: BACKGROUND
  A formulation containing 39.6% spinetoram resulted in a higher than anticipated number of reports of alopecia at the site of application in the first months following commercial product launch.
  
  
  OBJECTIVE
  To determine the cause of the alopecia using histopathology, including assessment for inflammation, follicular findings of physical trauma (plucking/pulling behaviour) and changes in follicular cycling.
  
  
  METHODS
  Twenty-four flea-free, male and female adult domestic short hair cats within a private research colony.
  
  
  METHODS
  Cats were treated with a single application of 39.6% spinetoram on day 0; personnel were not blinded. Observations of the skin and hair coat began immediately and were repeated at 30 min and 1, 2, 3, 4, 6, 8 and 12 h post-application and then on subsequent days at the same time as initial dosing and at 2, 4, 6, 8 and 12 h after that time, until day 5. If hair thinning or loss was observed, a skin biopsy sample was collected. Two cats not exhibiting abnormalities were biopsied on day 6.
  
  
  RESULTS
  Thirty-eight per cent of cats (nine of 24) developed hair thinning and alopecia of sufficient severity within 78 h post-application of the product to warrant skin biopsy. Abnormalities in the skin were limited to the application site and were consistent with physical trauma (pulling or plucking) to the hair.
  
  
  CONCLUSIONS
  Microscopic changes in the hair follicles of affected cats were consistent with self-induced trauma or barbering behaviour. All changes were reversible and paralleled findings associated with well-established, topical flea control products.
authors.affiliation: Eli Lilly and Company, 355 East Merrill Street, Indianapolis, IN, 46285, USA.
authors.forename: Kelly M
authors.initials: KM
authors.lastname: Credille
authors.forename: Lori A
authors.initials: LA
authors.lastname: Thompson
authors.forename: Lisa M
authors.initials: LM
authors.lastname: Young
authors.forename: Jeffery A
authors.initials: JA
authors.lastname: Meyer
authors.forename: Joseph R
authors.initials: JR
authors.lastname: Winkle
mesh_terms: D000287:Administration, Topical; D000505:Alopecia / Q000139:chemically induced / Q000662:veterinary*; D000818:Animals; D002371:Cat Diseases / Q000139:chemically induced*; D002415:Cats; D005260:Female; D058267:Flea Infestations / Q000517:prevention & control / Q000662:veterinary*; D007306:Insecticides / Q000009:adverse effects* / Q000494:pharmacology; D018942:Macrolides / Q000009:adverse effects* / Q000494:pharmacology; D008297:Male
chemical_list: D007306:Insecticides; D018942:Macrolides; C548262:spinetoram